1. Field of the Invention
The present invention relates to a valve system for an engine, including a valve resting mechanism provided between an engine valve and a valve lifter supported by a cylinder head so as to be slidably driven by a valve system cam. The valve resting mechanism is capable of switching an acting state and a non-acting state of a pressing force applied from the valve lifter to the engine valve in the valve opening direction and turning, in the non-acting state of the pressing force, the engine valve into the resting state irrespective of the sliding motion of the valve lifter.
2. Related Art
A valve system of this type has been known, for example, from Japanese Utility Model Publication No. Hei 3-7526. In a valve resting mechanism of the valve system disclosed in this document, a slide pin having a containing hole capable of containing the leading end of a valve stem of an engine valve is directly fitted in a valve lifter supported in a cylinder head so as to be slidably driven by a valve system cam. The rotation of the slide pin around its axis is prevented by fitting the leading end of the valve stem in a groove formed in a pin holder.
The above valve resting mechanism, however, has a disadvantage: The rotation stop of the slide pin is achieved in a state in which the valve resting mechanism is assembled in the valve stem of the engine valve. In other words, the rotation stop of the slide pin with respect to the valve lifter is not achieved in the step of assembling the valve resting mechanism. As a result, it is difficult to align the groove of the pin holder with the leading end of the valve stem upon assembly of the valve lifter in the cylinder head. This complicates the step of assembling the valve resting mechanism.
In view of the foregoing, an object of the present invention is to provide a valve system for an engine valve which facilitates the work of assembling a valve resting mechanism.